Harriot's maps of the moon : new interpretations

Abstract

July 2009 is the 400th anniversary of the first telescopic observations of the Moon, made by the English scientist Thomas Harriot. Galileo's later drawings were more influential, but some historians now question the traditional view that Harriot's were inferior. Galileo's revealed the mountainous topography of the Moon, but Harriot's arguably had the different, cartographical aim of plotting lunar features precisely. This article suggests that, influenced by the remarkable work of his contemporary William Gilbert, Harriot may have devised or used his splendid Moon map, like Gilbert, to observe the phenomenon of lunar libration decades before Galileo announced its existence.